Women walk past a UN peacekeeper outside the protection of civilian camp in Bentiu. The UN human rights council has been urged to deploy a 4,000-strong protection force in South Sudan.
Photograph: Kate Holt/Unicef

Conditions in South Sudan were repeatedly likened to those in Rwanda on the eve of its genocide at a special session of the UN human rights council held on Wednesday, with a top official warning that escalating ethnic violence has left the country teetering on the brink of disaster.

On the third anniversary of the civil war in the world’s youngest country, members states heard that swift action was required to prevent a genocide, including targeted sanctions and the deployment of a 4,000-strong protection force to separate the warring parties.

The meeting heard severe criticism of the role of the existing UN peacekeepers in South Sudan, who risked becoming “guilty bystanders” to atrocities.

Violence in South Sudan orchestrated by government, UN report reveals

Amid warnings of an “all-out ethnic civil war”, the meeting in Geneva was advised that violence in South Sudan could destabilise the wider east Africa region.

“With the beginning of the dry season South Sudan teeters on the brink of a disaster,” said Zeid Ra’ad al-Hussein, the UN high commissioner for human rights.

“Weather conditions mean armed groups, militias and bandits can roam more swiftly across the landscape and there is a high potential for clashes between the government and fighters on multiple fronts.”

Tens of thousands have been killed in fighting in South Sudan, and more than a million people have fled the country.

Zeid said that threats of violence decreased when local leaders intervened recently to halt hate speech, suggesting “there may still be some space for consequential action to pull the country back from a worst-case scenario”.

He called on the African Union to act quickly in setting up a court “with a strong focus on command responsibility for atrocities”.

The scale of sexual violence perpetrated by all sides in the conflict already matches that of the war in Bosnia, said Yasmin Sooka, chair of the UN commission on human rights in South Sudan.

Sooka described what she had found on the ground in South Sudan during a recent visit. “In a meeting with displaced women we were challenged [about] why we had wasted money on plane tickets when the international community looks on and does nothing. The rest of the crowd applauded.”

Kuol Alor Kuol Arop, South Sudan’s permanent representative to the UN in Geneva, said there was no justification for the special sessions.

“From the outset, and without going into the substance of the glaring allegations, I would like to reiterate and affirm that my country, as a responsible member of the international community, is ready and keen to cooperate with the UN and its various institutions,” he said.

South Sudan’s position was supported by Venezuela, whose representative said the allegations were based on unreliable information and assumptions. The motives of some at the council were fuelled by a “neoliberal appetite”, he said.

In a televised address, Adama Dieng, the UN special adviser on the prevention of genocide, said states urgently needed to impose an arms embargo, stressing that it would have an important impact. “I see no valid reasons to delay,” said Dieng.

Dieng also suggested that members of the South Sudanese diaspora had contributed to the hate speech and violence.

“Genocide is a process, it does not happen overnight, and because it is a process that takes time to prepare it can be prevented,” he said. “There are steps that can be taken now without delay.”

Violence erupted in South Sudan in December 2013 when President Salva Kiir accused his vice-president, Riek Machar, of plotting a coup. The country gained independence from Sudan in 2011 following one of Africa’s longest running conflicts.

Reuters reported this week that Machar, who fled to the Democratic Republic of the Congo in August, is being detained in South Africa. Foreign ministry spokesman Clayson Monyela said he was a guest of Pretoria as South Africa tried to prevent the civil war sliding into genocide.

Dickson Gatluak, a spokesman for Machar in Ethiopia, denied there were any restrictions on the former vice-president.

The special session of the UN human rights council was requested by 40 states, led by the US. The US representative expressed particular alarm at ethnic violence in South Sudan’s southern Equatoria region, a relative haven from violence until recently.

“We condemn the government’s crackdown on all forms of dissent, including against journalists and human rights defenders,” he said.

In July, following a surge in violence in Juba, the South Sudanese capital, a 4,000-strong regional protection force was authorised to deploy as part of the UN Mission in South Sudan to protect civilians. However, the South Sudanese government only agreed to accept the deployment of the foreign troops on its territory last month.

UN Watch demanded “immediate and meaningful action” in support the survivors of violence.

“Strengthening the UN presence in the country and instructing them to protect civilians would be an important start,” said Leon Saltiel, UN Watch’s representative.